Thousands of bodies are already cryonically frozen, waiting for faster computers and medical advances that will undo their cause of death

What is death? Over the centuries, the line dividing life and death has moved from the cessation first of breathing, then of the heartbeat, and finally of brain activity. But cryogenic methods first contemplated in science fiction may push the line even further. The idea is to freeze legally dead people in liquid nitrogen in the hope of regenerating them at some future date. Today’s cryonics scientists believe that this future may be a mere 100 years away. Alcor Life Extension Foundation, in Scottsdale, Ariz., the world’s largest cryonics company, charges US $150 000 to freeze and maintain a body and $80 000 for a head, typically paid for with a life insurance policy.

Ralph Merkle, a nanotechnology expert and a director at Alcor, believes the best approach lies in developing nanorobots that can repair the body at the cellular level before thawing. They would fix or replace diseased and deteriorated tissue as well as the tissue fractures and denatured proteins that result from the freezing process itself. The revival process would, ideally, restore the physiology of dead persons to a pristine level, not only undoing the damage of whatever disease or accident killed them but also enabling them to return smarter and healthier than they ever were in life.

”We’re talking about a fundamentally more powerful medical technology than we have today that will continue the evolution of the concepts of life and death,” says Merkle, who holds bachelor’s and master’s degrees in computer science from the University of California, Berkeley, and a Ph.D. in electrical engineering from Stanford. ”People will be able to suffer more damage and still fully recover.”

Before the body is cooled to –196 °C (the temperature at which liquid nitrogen becomes a gas), the person’s blood is replaced by a cryoprotective solution that doesn’t freeze at those temperatures. Technically, the body and cryoprotective solution are not frozen but vitrified—that is, they solidify into a glassy substance that’s free of ice crystals and the damage they can cause. The first step in the future regeneration process would remove this vitrified liquid, letting physicians use the circulatory system as a series of tunnels through which they could run nanomedical robots, nanomaterials, and a removable high-speed fiber-optic network connecting to an external supercomputer.

Photo: Alcor Life Extension Foundation
Chill out: For a mere US $150 000, you can deliver your corpse to the cryogenicists at the Alcor Life Extension Foundation and wait for medical science to conquer death.

”It takes about 1025 bits to store the molecular structure of the brain,” says Merkle. ”The processing power to repair the brain alone might be 1037 switching operations (1031 floating-point operations)—the equivalent of 100 million copies of today’s fastest supercomputer running flat out for three years. With Moore’s Law doubling computer power every year, we’ll have that kind of computational power in a single supercomputer in about 26 years,” he adds. ”Give it another 10 years and the price will drop from $100 million to $100 000. Somewhere around 2050, that much computational power will be readily available to individuals.” And it doesn’t matter if Moore’s Law slows down, Merkle says: ”A person at the temperature of liquid nitrogen can literally wait centuries.”

That loose deadline was a selling point for Merkle when he first investigated life-extension technologies for himself and his wife. Cryonics offered the only potential solution that wasn’t tied to a person’s lifetime.

But is it a solution—or a pointless gamble? In The Skeptics Dictionary: A Collection of Strange Beliefs, Amusing Deceptions, and Dangerous Delusions (Wiley, 2003), retired philosophy professor Robert Todd Carroll wrote: ”A business based on little more than hope for developments that can be imagined by science is quackery. There is little reason to believe that the promises of cryonics will ever be fulfilled.”

Stephen Barrett, a retired psychiatrist in Chapel Hill, N.C., who operates the Web site Quackwatch, a health-care consumer-advocacy network, agrees. ”The odds are pretty close to zero that people who are pronounced dead would have any remaining brain function or restorability. Brain cells die fairly quickly and would have to be regenerated in sufficient order and numbers to restore functionality. And then you’d have to restore the rest of the body. The obstacles are so enormous, it’s a foolish investment. You’re better off putting the money toward improving your life today or doing something worthwhile for others.”